The present invention relates generally to coupling means for a snow plow and, more specifically, to automatic coupling and uncoupling means.
A conventional snow plow includes framework which is fixed to the back of the plow. The framework is adapted to be connected to an "A-frame" which is provided with hydraulic actuating means for angling the plow. The "A-frame" is also provided with coupling means for coupling with complimentary coupling means of framework which is attached to the front of the plow vehicle. This latter framework is generally referred to as a "pushbeam" and includes a pair of spaced guides for receiving a pair of spaced tabs which extend rearwardly from the "A-frame". Each tab has a plurality of apertures and is adapted to fit into one of the guides of the "push beam". A retractable connecting pin is associated with each guide. The pin extends laterally through apertures in the guide and through one of the apertures of the tab, when the tab is positioned within the guide, so that one of the apertures of the tab is axially aligned with the apertures of the guide.
During periods when the plow is not being used, it is disconnected from the vehicle and stored in a location where the vehicle can be driven up to the "A-frame" of the plow for recoupling. Normally, the "A-frame" is mounted on blocks at a height which enables the tabs to be at the same height as the guides in the "push beam". The connecting pins are pulled out of the guides and the vehicle is advanced toward the A-frame, so that the tabs enter the guides. Most of the time, the apertures in the guides are misaligned with the apertures in the tabs. The tabs are aligned within the guides by means of lift chains which are connected to a hydraulically operated lever in the vehicle. After the apertures in the guides are aligned with corresponding apertures in the tabs, the connecting pins are reinserted into the guides and through the tabs. The entire operation of coupling the plow to the plow vehicle is awkward and time-consuming, particularly if the entire operation is performed by a single individual. First of all, it is extremely difficult for an individual to advance the vehicle toward the "A-frame", so that the tabs are horizontally aligned with the guides. Very often, several attempts must be made before the tabs are generally aligned with the guides, so that they can be advanced into the guides. The individual must make several trips into and out of the vehicle. When the operation is performed by two individuals, one individual can stay in the vehicle while the other individual attempts to direct the movement progress of the vehicle. Even with two individuals, several reciprocations of the vehicle must be made before the tabs are aligned within the guides. Thereafter, the "A-frame" must be manipulated vertically to properly align the apertures of the guide with corresponding apertures in the tabs. Under ideal weather conditions, the entire coupling operation is difficult enough. However, most of the time weather conditions are substantially less than ideal. Due to the purpose for which snowplows are used, coupling typically occurs during stormy and cold conditions. In addition, most snowplowing begins in the early morning hours when it is dark. There is always a certain degree of emergency to get started and coupling under less than ideal conditions can be very frustrating to the operator. These and other dificulties experienced with the prior art devices have been obviated by the present invention.
It is, therefore, a principal object of the present invention to provide a plow coupling which enables a plow to be coupled and uncoupled automatically.
Another object of this invention is the provision of a plow coupling which does not require connecting pins.
A further object of the present invention is the provision of a mounting tab which is adaptable to a conventional plow coupling for providing automatic coupling and uncoupling of a plow.
It is another object of the present invention to provide an automatic plow coupling which does not require precise, vertical, or horizontal orientation of the plow vehicle relative to the plow.
A still further object of the invention is the provision of releasable connecting means for automatic uncoupling of an automatic plow coupling.
It is a still further object of the invention is to provide an automatic plow coupling which is simple in construction, which is inexpensive to manufacture, and which is capable of a long life of useful service with no maintenance.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.